HDR, IR Imagery and Tone mapping!

This entry is more a summary of my experience using IR and HDR. My earlier entry in Singapore was only an initial experience. I am now back in Australia and travelled directly to Daylesford in central Victoria to my parents future home. The house is a very old “Grey Sisters” convent that has been in our family’s name for over 40 years now. It is to be completely redeveloped shortly but that’s another story – I want to talk about High Dynamic Imagery and Infra Red photography.

In Singapore I bought an IR filter (a seriously dark red filter that cost about $230). By simply screwing this filter to my 24-105mm zoom lens, I effectively filter the light to provide the sensor with shades of Red light. To compensate for such a heavy filter, I have had to set my ISO to 1000 and the exposure time roughly between 1/4 of a second and 5 seconds. Thats using my 5D mark1! So this is best done on a tripod. After setting the framing (by removing the filter for a moment so I could actually see something through the viewfinder) I shot several exposures above and below what I considered to be normal. Off-course all my images were shot in RAW, however I also shot a Black and White Jpeg in camera for reviewing on the camera’s LCD. The next stage after importing these images into my Mac, was to generate a HDR image. That’s a High Dynamic Range Image. This is done by combining all the bracketed exposures from each set of shots using Photoshop’s automated process. You could simply play with Brightness and Contrast etc and derive a pretty awesome image from this but there is another secret ingredient. Tonemapping!

I use a program called Photomatrix Pro. It’s a standalone and plugin based program that works with Photoshop. I find the standalone version best. With Photomatrix, you simply create the HDR image using it’s automated process. It’s pretty clever to adjust any differences in vertical and horizontal alignment for you, which is nice. After it has produced the HDR image, you click on the next step which is to adjust the HDR’s Tonal range – this is called Tonemapping. By playing with the White and Black point, desaturating the image and general Gamma settings, you can create some stunning Infra Red, Black and White photographs. I save these out as 16-bit Tifs and then open them up in Photoshop. Here I adjust the levels to be a bit more punchy and sometimes play with the Shadow/Highlight settings. After this, the image is saved and converted into an 8-Bit version before sizing down and exporting as a Jpeg to this website.

One thing to note while you are shooting this type of image – It looks best to me when there was some direct unfiltered sunlight. This created hard shadows on the ground which look fantastic. Also, having light green colours somewhere in the frame, preferably backlit helped to emphasis the Infra Red quality of the image. Light Green off-course renders as light grey in Black and White, but through the IR filter becomes almost pure white! My last tip is to shoot fast and try to stop all objects from moving in the scene. As the images are combined into one file, any movement between the frames creates artifacts that you might not want. Additionally, movement within an exposure (especially the long exposures) will appear as soft or blurry! This will further degrade the sharpness of your final image. The process is lengthy but the results I think are well worth the effort. Cheers!